The government in India's north-eastern state of Assam is recruiting 700 surrendered rebels as "special police officers" to fight separatists.

Assam police's additional director-general Khagen Sarma told the BBC that they would be initially recruited on a "temporary basis" for a few months.

He said that their conduct and performance would be reviewed before their "service is regularised".

The insurgency in Assam has been one of the longest-running in India.

'Huge fortunes'

Police want to ensure that "unwanted elements" are not inducted, says Mr Sarma, who heads the intelligence wing of the state police.

"Some of the surrendered militants are unruly and would be difficult to control. We don't want them.

"Also we want to make sure that they are capable of contributing to the counter-insurgency."

The surrendered militants belong to a host of rebel groups including the United Liberation Front of Assam (Ulfa), National Democratic Front of Bodoland (NDFB), Muslim United Liberation Tigers of Assam (Multa) and Karbi Longri National Liberation Front (KLNLF).

While the Ulfa is still fighting for Assam's independence from India, the other groups say they are fighting for separate homelands for their tribes. The Multa is an Islamic radical group that says it wants to avenge attacks and torture on Muslims in Assam.

The Indian home ministry reimburses insurgency-affected states for the salaries of "special police officers".

The army has confiscated large arms hauls
from surrendered rebels​

Scores of surrendered insurgents have been recruited in this way in other parts of India - including the Maoist-affected state of Chhattisgarh and the insurgency-hit state of Tripura in the north-east.

The surrendered militants in Assam are already protesting over their proposed pay.

They say the government had promised 4,500 rupees ($100) a month but will now pay them only 3,000 rupees.